Chennai: The exciting phase of India's second lunar mission, Chandrayaan-2, has just began. On wee hours of Wednesday, the spacecraft has successfully entered lunar transfer trajectory and is expected to reach Moon's orbit on August 20.
At 2.20 am, Indian Space Research Organisation (Isro) has performed the crucial Trans-Lunar Insertion (TLI) operation firing on-board liquid engine for about 1203 seconds (20 minutes) in order to catapult the spacecraft away from Earth's orbit to lunar trajectory. Earlier, the spacecraft’s orbit was progressively increased five times during July 23 to August 6.
In a statement, ISRO said: "The health of the spacecraft is being continuously monitored from the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking and Command Network (ISTRAC) in Bengaluru with support from Indian Deep Space Network (IDSN) antennas at Byalalu. Since its launch on July 22, all systems on-board Chandrayaan-2 spacecraft are performing normal."
Officials said Chandrayaan-2 will approach Moon on August 20 and the spacecraft's liquid engine will be fired again to insert the spacecraft into a lunar orbit. Following this, there will be further four orbit maneuvers during August 21 to September 1 to make the spacecraft enter into its final orbit passing over the lunar poles at a distance of about 100 km from the Moon’s surface.
"Subsequently, Vikram lander will separate from the orbiter on September 2. Two orbit maneuvers will be performed on the lander before the initiation of powered descent to make a soft landing on the lunar surface on September 7," Isro said.
Isro chairman K Sivan had described the descending phase (attempt to soft-land) as "15 minutes of terror" as the margin of error is minimal. Variation in local gravity has to be factored and the on-board Navigation and Control (NGC) and propulsion system has to work in unison, autonomously and automatically for a successful landing. Further, the landing site landscape features should not result in a communication shadow area.
During an interview with Express, NASA Chief Scientist Jim L Green said the american space agency was looking forward for what Chandrayaan-2 would unravel as NASA would use the data for its proposed moon programme - Artemis. NASA has worked with ISRO to install a laser retroreflector on the Chandrayaan-2 lunar lander.
1. Chandrayaan-2 has left Earth on Wednesday and moving towards moon.
2. The spacecraft would reach initial orbit of moon on August 20.
3. Soft landing near uncharted south pole would be attempted on September 7.
4. If Isro manages to successfully land Vikram on Moon, India will
enter an elite club of nationals to have done this before - US,
erstwhile USSR and China.
Tentative plan for future operation after TLI:
| Date | Time | Orbit around moon |
| August 20 | 8.30 am-9.30 am | 118 x 18078 |
| August 21 | 12.30 pm-13.30 pm | 121 x 4303 |
| August 28 | 5.30 am-6.30 am | 178 x 1411 |
| August 30 | 6 pm-7 pm | 126 x 164 |
| September 1 | 6 pm - 7 pm | 114 x 128 |